title: Resistance of Staphylococcus aureus to the cationic antimicrobial agent poly(2-(dimethylamino ethyl)methacrylate) (pDMAEMA) is influenced by cell-surface charge and hydrophobicity.
abstract: Cationic antimicrobial agents may prevent device-associated infections caused by Staphylococcus epidermidis and Staphylococcus aureus. This study reports that the cationic antimicrobial polymer poly(2-(dimethylamino ethyl)methacrylate) (pDMAEMA) was more effective at antagonizing growth of clinical isolates of S. epidermidis than of S. aureus. Importantly, mature S. epidermidis biofilms were significantly inactivated by pDMAEMA. The S. aureus isolates tested were generally more hydrophobic than the S. epidermidis isolates and had a less negative charge, although a number of individual S. aureus and S. epidermidis clinical isolates had similar surface hydrophobicity and charge values. Fluorescence spectroscopy and flow cytometry revealed that fluorescently labelled pDMAEMA interacted strongly with S. epidermidis compared with S. aureus. S. aureus ΔdltA and ΔmprF mutants were less hydrophobic and therefore more susceptible to pDMAEMA than wild-type S. aureus. Although the different susceptibility of S. epidermidis and S. aureus isolates to pDMAEMA is complex, influenced in part by surface hydrophobicity and charge, these findings nevertheless reveal the potential of pDMAEMA to treat S. epidermidis infections.
authors.affiliation: Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.|School of Agriculture, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Lee-Anne B
authors.initials: LB
authors.lastname: Rawlinson
authors.affiliation: School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland.|Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: James P
authors.initials: JP
authors.lastname: O'Gara
authors.affiliation: School of Pharmacy, Queen's University of Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: David S
authors.initials: DS
authors.lastname: Jones
authors.affiliation: Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.|School of Agriculture, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: David J
authors.initials: DJ
authors.lastname: Brayden
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002462:Cell Membrane; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial; D057927:Hydrophobic and Hydrophilic Interactions; D008564:Membrane Potentials / Q000187:drug effects; D008689:Methacrylates / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009757:Nylons / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013212:Staphylococcus epidermidis / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D008689:Methacrylates; D009757:Nylons; C407037:poly(2-(dimethylamino)ethyl methacrylate)